High Curvature Bending of Viscoelastic Thin-Ply Composites

Abstract

This paper presents a micromechanical model for viscoelastic analysis of thin-ply composites. The thin-ply laminate is modeled as a Kirchhoff plate with viscoelastic properties described by its relaxation ABD stiffness matrix. Unit cell homogenizations are conducted at two scales to evaluate the relaxation ABD matrix. A single fiber-matrix model is first employed to evaluate the properties of a unidirectional tow. The computed tow properties are utilized in a laminate model that explicitly represent the weave geometry and ply configuration derived from micrographic analysis. Boundary conditions that enforce the Kirchhoff plate assumptions are imposed on the laminate model to determine the relaxation ABD matrix. Unit cell homogenizations are carried out via the finite element method. The model is applied to a 4-ply plain-weave thin-ply composite. The behavior of thin-ply composite at high bending curvatures and specifically studied for deployable spacecraft structure applications. The viscoelastic response is found to be dependent phase configuration of the plies. Geometrically nonlinear response is also observed at high curvatures.